Portable exercise devices are well known. They have evolved from simple hand weights to elaborate electro-mechanical devices which offer various types of resistance elements that the user engages to introduce resistance to various muscle groups.
One category of portable exercise devices involves the use of one or more wheels attached to a shaft where the user engages his or her hands or feet with the shaft and proceeds to roll the wheels back and forth to engage specific muscle groups. For example, in U.S. Pat. No. 4,595,197 by D Hagstrom et al describes a two wheeled exercise device where the user either advances the wheels with his hands or feet to cause various muscles to be worked. U.S. Pat. No. 6,017,296 by J. Tang describes an exercise wheel assembly that has an internal resistance band to cause the wheel to be harder to push along a floor as distance increases.
Another category of exercise devices has been developed to help the user perform Pilates type exercises. Pilates is a body conditioning routine that helps build flexibility, muscle strength, and endurance in the legs, abdominals, arms, hips, and back. It puts emphasis on spinal and pelvic alignment, breathing, and developing a strong core or center, and improving coordination and balance. Pilates' system allows for different exercises to be modified in range of difficulty from beginning to advanced. Intensity can be increased over time as the body conditions and adapts to the exercise. Various pieces of equipment have been designed and marketed to facilitate Pilates exercise; however, they tend to be expensive, large and heavy assemblies that are usually found in dedicated Pilates exercise studios. The bulky equipment restricts the possibility for a person to practice Pilates exercises in the privacy of their own home unless they are willing to invest in commercial grade equipment and have the available square footage in their home to accommodate the large size of the standard equipment.